Air India abruptly stopped 19 Indian students from flying to San Francisco for studies.

Nineteen Indian college students were barred from boarding an Air India flight bound for San Francisco Sunday night after authorities suddenly told them their American schools were under “scrutiny” for reasons unknown.

The bizarre barring of the students at Hyderabad’s Rajiv Gandhi International Airport — all of whom were due at Bay Area schools — apparently came from past problems of students studying at those colleges, the airline said.

“In the past, we have witnessed that students who secured admission in those institutions have been deported to India as soon as they land there,” an Air India official told Huffington Post India.

“To avoid embarrassment to them and save their money, we prevented them from boarding the flight.”

The airline added in a statement that the U.S. Customs and Border Protection Agency warned the airline the day of the flight that the students were not allowed in America and would be deported back to India.

Air India offered all 19 students refunds on their no-go flights.

But the grounded students were still left with soar feeling, wondering why they were granted visas in the first place if there would be problems.

“We were treated like criminals and sent back,” one student, who did not give a name, told the Times of India.

Customs officials did not immediately comment to the Daily News.

The two schools supposedly under scrutiny — Silicon Valley University in San Jose, and Northwestern Polytechnic in Fremont — denied that they are under any government watch. The schools said the students got stuck in India due to individual problems at customs.